scholarly journals Noncooled (Hg,Cd)Te IR photo detectors in range of 10.6 μm wavelength

2018 ◽  
Vol 19 (12) ◽  
pp. 795-801
Author(s):  
Tadeusz Niedziela
Keyword(s):  
Room Temperature ◽  
Ohmic Contacts ◽  
Energy Gap ◽  
Optimal Parameters ◽  
Thermal Generation ◽  
Ir Radiation ◽  
Research Results ◽  
Parameter Evaluation ◽  
Carrier Recombination ◽  
Photo Detectors

In range of 10.6 μm IR radiation an analysis of noncooled (T = 300 K) (PC) photodiodes and (EMCD) magnetoexlusion detectors with (Hg,Cd)Te was made. The basic detection parameters of these devices are limited by the noise resulting from statistical processes of thermal generation and carrier recombination. The parameter evaluation of related photodiodes demonstrates that the optimal parameters such as: thickness or structure doping on the substrate with a widened energy gap differs each other for structures with ohmic contacts at both ends. In the paper, for photodiodes and magnetoexclusion detectors with (Hg,Cd)Te the research results : optimal photosensitive detection parameters are presented for the room temperature (T=300 K) and acceptable large as well as small (5 and 0.5 W / mm2) densities of the dissipated power.

scholarly journals Fabrication of Graphene Nanomesh FET Terahertz Detector

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 641
Author(s):  
Yuan Zhai ◽  
Yi Xiang ◽  
Weiqing Yuan ◽  
Gang Chen ◽  
Jinliang Shi ◽  
...  
Keyword(s):  
Room Temperature ◽  
Energy Gap ◽  
Coupling Efficiency ◽  
High Sensitivity ◽  
Fabrication Process ◽  
Monolayer Graphene ◽  
Terahertz Waves ◽  
Wet Process ◽  
Graphene Nanomesh ◽  
Thz Detector

High sensitivity detection of terahertz waves can be achieved with a graphene nanomesh as grating to improve the coupling efficiency of the incident terahertz waves and using a graphene nanostructure energy gap to enhance the excitation of plasmon. Herein, the fabrication process of the FET THz detector based on the rectangular GNM (r-GNM) is designed, and the THz detector is developed, including the CVD growth and the wet-process transfer of high quality monolayer graphene films, preparation of r-GNM by electron-beam lithography and oxygen plasma etching, and the fabrication of the gate electrodes on the Si3N4 dielectric layer. The problem that the conductive metal is easy to peel off during the fabrication process of the GNM THz device is mainly discussed. The photoelectric performance of the detector was tested at room temperature. The experimental results show that the sensitivity of the detector is 2.5 A/W (@ 3 THz) at room temperature.

Long Luminescence Lifetime of 1.54 μ m Er3+ Luminescence from Erbium Doped Silicon Rich Silicon Oxide and its Origin

1998 ◽  
Vol 536 ◽  
Author(s):  
Se-Young Seo ◽  
Jung H. Shin ◽  
Choochon Lee
Keyword(s):  
Room Temperature ◽  
Radiative Decay ◽  
Silicon Oxide ◽  
Silicon Nanoclusters ◽  
Excitation Rate ◽  
Carrier Recombination ◽  
Erbium Doped ◽  
Doped Silicon ◽  
Almost All ◽  
Er Doped

AbstractThe photoluminescent properties of erbium doped silicon rich silicon oxide (SRSO) is investigated. The silicon content of SRSO was varied from 43 to 33 at. % and Er concentration was 0.4–0.7 at. % in all cases. We observe strong 1.54 μ m luminescence due to 4I13/2⇒4I15/2 Er3+ 4f transition, excited via energy transfer from carrier recombination in silicon nanoclusters to Er 4f shells. The luminescent lifetimes at the room temperature are found to be 4–7 msec, which is longer than that reported from Er in any semiconducting host material, and comparable to that of Er doped SiO2 and A12O3. The dependence of the Er3+ luminescent intensities and lifetimes on temperature, pump power and on background illumination shows that by using SRSO, almost all non-radiative decay paths of excited Er3+ can be effectively suppressed, and that such suppression is more important than increasing excitation rate of Er3+. A planar waveguide using Er doped SRSO is also demonstrated.

scholarly journals Spectral Properties of Hybrid of Rhodamine (6G) Dyes Doped Epoxy Resin Dissolved in Chloroform

2019 ◽  
Vol 16 (3(Suppl.)) ◽  
pp. 0764 ◽  
Author(s):  
Al-Hamdani Et al.
Keyword(s):  
Epoxy Resin ◽  
Quantum Efficiency ◽  
Fluorescence Spectra ◽  
Room Temperature ◽  
Rhodamine 6G ◽  
Energy Gap ◽  
Radiative Lifetime ◽  
Stokes Shift ◽  
Fluorescence Emission ◽  
Absorption And Fluorescence Spectra

            The research is dealing with the absorption and fluorescence spectra for the hybrid of  an Epoxy Resin doped with organic dye Rhodamine (R6G) of different concentrations (5*10-6, 5*10-5, 1*10-5, 1*10-4, 5*10-4) Mol/ℓ at room temperature. The Quantum efficiency Qfm, the rate of fluorescence emission Kfm (s-1), the non-radiative lifetime τfm (s), fluorescence lifetime τf and the Stokes shift were calculated. Also the energy gap (Eg) for each dye concentration was evaluated. The results showed that the maximum quantum efficiency 62 % and maximum stokes shift 96 nm was obtained in dye concentration 5*10-6 and 1*10-4. The energy gap ranges between 1.066 eV to 1.128 eV depending proportionally on the dye concentrations.

scholarly journals Optical and Structural Properties of CdS Quantum Dots Synthesized Using (MW-CBD) Technique

2020 ◽  
pp. 44-52
Author(s):  
Ahmed Ahmed S. Abed ◽  
Sattar J. Kasim ◽  
Abbas F. Abbas
Keyword(s):  
Thin Films ◽  
Quantum Dots ◽  
Room Temperature ◽  
Energy Gap ◽  
Cds Nanoparticles ◽  
Cds Quantum Dots ◽  
Optical Energy Gap ◽  
Glass Substrates ◽  
High Adhesion ◽  
Uv Visible

In the present study, the microwave heating method was used to prepare cadmium sulfide quantum dots CdSQDs films. CdS nanoparticles size average obtained as (7nm). The morphology, structure and composition of prepared CdSQDs were examined using (FE-SEM), (XRD) and (EDX). Optical properties of CdSQDs thin films formed and deposited onto glass substrates have been studied at room temperature using UV/ Visible spectrophotometer within the wavelength of (300-800nm), and Photoluminescence (PL) spectrum. The optical energy gap (Eg) which estimated using Tauc relation was equal (2.6eV). Prepared CdS nanoparticles thin films are free from cracks, pinholes and have high adhesion to substrate.

Deposition of Thin Films of Silicon Carbide on Fused Quartz and on Sapphire by Laser Ablation of Ceramic Silicon Carbide Targets

1992 ◽  
Vol 285 ◽  
Author(s):  
L. Rimai ◽  
R. Ager ◽  
J. Hangas ◽  
E. M. Loaothetis ◽  
Nayef Abu-ageel ◽  
...  
Keyword(s):  
Thin Films ◽  
Silicon Carbide ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Energy Gap ◽  
Fused Silica ◽  
High Resistivity ◽  
Fused Quartz ◽  
Amorphous Sic ◽  
Very High

ABSTRACTAblation of ceramic silicon carbide with 351 nm excimer radiation was used to depositSIC films on fused silica and on sapphire. For deposition temperatures above 850° C, diffraction shows the films to be crystalline with the [111] axis preferentially oriented normally to the film. Optical spectra show an indirect energy gap at 2.2 eV, near that for the cubic polytype, although the 200 diffractions are absent. Room temperature resistivities range between .02 to .1 Ωcm. Deposition below 600° C yields amorphous SiC with no diffraction bands, low and variable optical band gap and very high resistivity.

Optical Detection of Band Gap Variations Due to Ordering in Ga0.47In0.53As on InP

1992 ◽  
Vol 281 ◽  
Author(s):  
D. J. Arent ◽  
K. A. Bertness ◽  
Sarah R. Kurtz ◽  
M. Bode ◽  
J. M. Olson
Keyword(s):  
Band Gap ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Energy Gap ◽  
Growth Conditions ◽  
Band Gap Energy ◽  
Optical Energy Gap ◽  
Lower Growth ◽  
Transmission Electron ◽  
High Resolution Images

ABSTRACTA reduction in the optical energy gap of more than 65 meV has been observed in In0.53Ga0.47 As grown on (100) InP by atmospheric pressure metalorganic vapor phase epitaxy. The band gap energies were deduced from room temperature photocurrent spectroscopic measurements, accounting for differences in composition and strain. Spontaneous CuPt type ordering of In and Ga atoms on the (111) subplanes of the InGaAs2 was confirmed by transmission electron microscopy. Superlattice signatures in the transmission micrographs were observed only for samples with associated reduced band gap energies, and were confirmed by visible double periodicity in high resolution images. In0.53Ga0.47 As was grown under a variety of conditions, some which promoted ordering. In general, lower growth temperatures and moderate (∼4 μ/hr) growth rates promoted a greater degree of ordering and reduction of the band gap energy. The influence of growth conditions on the ordered structure is considered within the context of current theories.

Ni-Al-Ti Ohmic Contacts with Preserved Form Factor and Few 10- 4 Ωcm2 Specific Resistance on 0.1-1 Ωcm p-Type 4H-SiC

2018 ◽  
Vol 924 ◽  
pp. 385-388 ◽  
Author(s):  
Roberta Nipoti ◽  
Maurizio Puzzanghera ◽  
Maria Concetta Canino ◽  
Giovanna Sozzi ◽  
Paolo Fedeli
Keyword(s):  
Form Factor ◽  
Contact Resistance ◽  
Contact Area ◽  
Room Temperature ◽  
Ohmic Contacts ◽  
Specific Resistance ◽  
Thickness Ratio ◽  
Specific Contact Resistance ◽  
Specific Contact ◽  
P Type

This study shows that a thin Ni film on Al/Ti/4H-SiC metal pads allows to preserve the pad form factor during a 1000 °C/2 min treatment, provided that the Al and Ti film thicknesses are sufficiently thin. Moreover, by reducing the Al to Ti thickness ratio, droplet formation in the contact area is avoided and a mirror-like appearance is obtained. This optimal contact morphology corresponds to a specific contact resistance of few 10-4Ωcm2at room temperature on p-type 4H-SiC with resistivity in the range 0.1 – 1 Ωcm.

scholarly journals Two-photon-excited ultralong organic room temperature phosphorescence by dual-channel triplet harvesting

2019 ◽  
Vol 10 (31) ◽  
pp. 7352-7357 ◽  
Author(s):  
Zhu Mao ◽  
Zhan Yang ◽  
Chao Xu ◽  
Zongliang Xie ◽  
Long Jiang ◽  
...  
Keyword(s):  
Room Temperature ◽  
Energy Gap ◽  
Infrared Laser ◽  
Concentration Quenching ◽  
Ambient Conditions ◽  
Room Temperature Phosphorescence ◽  
Small Energy ◽  
Two Photon ◽  
Dual Channel ◽  
Triplet Harvesting

Small energy gap boosts dual-channel triplet harvesting via TADF and UOP, which suppresses long-lived triplet concentration quenching. An infrared laser (808 nm) is able to induce persistent emission under ambient conditions.

scholarly journals Charge Density Wave and Narrow Energy Gap at Room Temperature in 2D Pb3–xSb1+xS4Te2−δ with Square Te Sheets

2017 ◽  
Vol 139 (32) ◽  
pp. 11271-11276 ◽  
Author(s):  
Haijie Chen ◽  
Christos D. Malliakas ◽  
Awadhesh Narayan ◽  
Lei Fang ◽  
Duck Young Chung ◽  
...  
Keyword(s):  
Charge Density ◽  
Charge Density Wave ◽  
Room Temperature ◽  
Energy Gap ◽  
Density Wave
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